"use strict";

process.env.BABEL_ENV = "production";
process.env.NODE_ENV = "production";

process.on("unhandledRejection", err => {
  throw err;
});

require("../config/env");

const path = require("path");
const chalk = require("chalk");
const fs = require("fs-extra");
const webpack = require("webpack");
const config = require("../config/webpack.config.prod");
const paths = require("../config/paths");
const checkRequiredFiles = require("react-dev-utils/checkRequiredFiles");
const formatWebpackMessages = require("react-dev-utils/formatWebpackMessages");
const printHostingInstructions = require("react-dev-utils/printHostingInstructions");
const FileSizeReporter = require("react-dev-utils/FileSizeReporter");
const printBuildError = require("react-dev-utils/printBuildError");

const measureFileSizesBeforeBuild =
  FileSizeReporter.measureFileSizesBeforeBuild;
const printFileSizesAfterBuild = FileSizeReporter.printFileSizesAfterBuild;
const useYarn = fs.existsSync(paths.yarnLockFile);

const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024;
const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024;

if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
  process.exit(1);
}

measureFileSizesBeforeBuild(paths.appBuild).then(previousFileSizes => {
  fs.emptyDirSync(paths.appBuild);
  copyPublicFolder();
  return build(previousFileSizes);
}).then(({ stats, previousFileSizes, warnings }) => {
    if (warnings.length) {
      console.log(chalk.yellow("Compiled with warnings.\n"));
      console.log(warnings.join("\n\n"));
      console.log(
        "\nSearch for the " +
        chalk.underline(chalk.yellow("keywords")) +
        " to learn more about each warning."
      );
      console.log(
        "To ignore, add " +
        chalk.cyan("// eslint-disable-next-line") +
        " to the line before.\n"
      );
    } else {
      console.log(chalk.green("Compiled successfully.\n"));
    }

    console.log("File sizes after gzip:\n");
    printFileSizesAfterBuild(
      stats,
      previousFileSizes,
      paths.appBuild,
      WARN_AFTER_BUNDLE_GZIP_SIZE,
      WARN_AFTER_CHUNK_GZIP_SIZE
    );
    console.log();

    const appPackage = require(paths.appPackageJson);
    const publicUrl = paths.publicUrl;
    const publicPath = config.output.publicPath;
    const buildFolder = path.relative(process.cwd(), paths.appBuild);
    printHostingInstructions(
      appPackage,
      publicUrl,
      publicPath,
      buildFolder,
      useYarn
    );
  },
  err => {
    console.log(chalk.red("Failed to compile.\n"));
    printBuildError(err);
    process.exit(1);
  });

function build(previousFileSizes) {
  console.log("Creating an optimized production build...");

  let compiler = webpack(config);
  return new Promise((resolve, reject) => {
    compiler.run((err, stats) => {
      if (err) {
        return reject(err);
      }
      const messages = formatWebpackMessages(stats.toJson({}, true));
      if (messages.errors.length) {
        // Only keep the first error. Others are often indicative
        // of the same problem, but confuse the reader with noise.
        if (messages.errors.length > 1) {
          messages.errors.length = 1;
        }
        return reject(new Error(messages.errors.join("\n\n")));
      }
      if (
        process.env.CI &&
        (typeof process.env.CI !== "string" ||
         process.env.CI.toLowerCase() !== "false") &&
        messages.warnings.length
      ) {
        console.log(
          chalk.yellow(
            "\nTreating warnings as errors because process.env.CI = true.\n" +
            "Most CI servers set it automatically.\n"
          )
        );
        return reject(new Error(messages.warnings.join("\n\n")));
      }
      return resolve({
        stats,
        previousFileSizes,
        warnings: messages.warnings,
      });
    });
  });
}

function copyPublicFolder() {
  fs.copySync(paths.appPublic, paths.appBuild, {
    dereference: true,
    filter: file => file !== paths.appHtml,
  });
}
